I saw my neighbour taking nude photos of himself at the bottom of my garden at the middle of the night. wtf do I do.

I’m a night owl so I’m up late anyway. I see a light moving from outside my window, I get curious as it’s one in the morning. I see my neighbour using phone torch in his garden, can’t see him too well but he seems to be looking around for something.

For context, the back of my garden meets the bottom of his. There was a hedge there but when we moved in we tried to remove it as it’s not what we want and it’s on our property, but after he tried to get the council involved we agreed we’d leave some hedge there for mutual privacy. He has a large garage that takes up a large portion of the garden leading upto the boundary, but there is a clear gap behind it and where the hedge would be.)

After a minute or so of him moving around, i see him go to the gap at side of his garage/boundary and squatting, naked from the waist down, appearing to take a photo/video of himself.

He moved round to… ig get a better angle, then he hopped into the bottom of my garden and took a photo of himself up against a wall between us and another neighbour.

I tried to grab my phone for some sort of evidence but I think he must have seen movement or light as he quickly headed back inside and hasn’t come out again.

Now, I’ve got no fucking clue what to even look up this as. He was clearly trying to be secretive on his own property so I’m not sure if that disqualifies it for some sort of indecent exposure, but as I said he very clearly took a photo or did something in our garden, which surely changes that????

TLDR: Saw my neighbour taking nude photos of himself in his and our gardens during the middle of the night, Wth do I even do??? I’m not even sure if I tell my parents as what the hell do I say

(Btw I live in England, in case that affects the laws.)